Nonslip tile



' KLEIN and- MILTON F.

Xi lvlo4b2 Patented Apr. 10, 1923.

UNITED STATES ABRAHAM ALBERT KLEIN AND MILTON EX Iference- PATENT OFFICE.

F. BEECHER, or woncEsrEn, mssacnu- SETTS, ASSIGNORS TO NORTON COMPANY, OF WORCESTER, MASSACHUSETTS, A

CORPORATION OF MASSACHUSETTS.

NoNsmr TILE.

llo Drawing. Application filed November To all whom it may concern:

Be 1t known that we ABRAHAM ALBERT the United States of America, residing at Worcester in the county of Worcester and State of 1 assachusetts, have invented certain new and useful Improvements in Nonslip Tiles, of which the following is a full, clear, and exact specification.

' This invention relates to safety treads and more particularly to tiles and terrazzo adapted for use on stairs, ramps, platforms and other places where pedestrian travel is heavy and there is large danger of accidents due to slipping thereon.

.As disclosed in the patent to J eppson and Dietz No. 1,292,953 of January 20, 1919, it has been proposed to make a non-slip surfacing of' extremely hard materials, such as crystalllne alumina and silicon carbide,

ave oun hat there is a tendency for such extremely hard and durable tiles to show some decrease in anti-slipping characteristics after prolonged usage under certain types of trafiic conditions. This is considered'to be due in part .to the pores becoming loaded with foreign bodies. Also, the abrasive grains and bond tend to wear down to a smooth surface and the-tread does not retain. its maximum safety properties or possess the capacity for self renewal to a sufficient extent. In such cases, the grains are apparently too hard and too firmly bonded together so that the tread cannot disintegrate to the slight extent required to maintain an abrading surface. At the same time, the ains must be bonded by a material, whil e softer. and somewhat brittle, which is tough enough to hold .the grains in place until their period of efliciency is t. As a further consideration, the e ectric furnace products heretofore utilized for such treads have been expensive and have required high temperature methods for bonding them into tiles of sufiicient strength and durability to resist premature 'dlsintegration by traflic usage; hence the use of safety treads has not been promoted to the fullest extent because of the initial cost of the tiles.

It is accordingly an object of our invenlEEOHER, citizens of 11, 1920. Serial no. 423,423.

in hardness from 7 to 9 on Mo s scale,

which possess desirable characteristics adapting them for non-slip purposes, and to employ those minerals to this end which are too fusible to be used in accordance with the former high temperature method of bonded by cegamic materials fused a? a high making ceramic tiles. temperature, approximate y 1 e A further object is to simplify the rocedure and lessen theexpense of bon ing granules of various types of anti-slipping material and yet obtain an article WhlCh is substantially weatherproof and highly resistant to disruption by pedestrian abrasions. Further objects will be apparent in the following disclosure.

In accordance with this invention, we pro- Examiner.

ceramic bonds which are'able to hold the grains in place for a longperiod under the ordinary usage of pedestrian trafiic. The various abraslve materials suitable for this pur ose, which are harder than quartz, inclu e the various spinel abrasives and particularly that spinel known as ma nesium as l aluminate, the such gigZEL-t 21.921511- aluminum s1l1ca e, cry and the low gra e emerys suc as eekskil emery, which contains a high percentage of iron oxide and may contain a large amount of the im s inel herc nite.

In or er to unite these grains into an integral mass of the proper density and comma R mate porosity, as well as tensile strength and mula and procedure may be adopted. A ability to withstand the shocks and strains dr mixture may be made up of of pedestrian wear, we propose to utilize Be 1 parts by weight various ceramic bonds, such as clay mate 7 r t c rials vitri?ing to a glassy or a po'rcelamc Zinc oxide- I I 1 Part condition or those materials which do not lban SH 1;" 2 arts soften or chan e at the tem erature of vity p rification of t e bond. T e various low To this dry mixture maybe added 9 parts b fusing silicates, such as sodium silicate, arc of wet sodlum s1l1catehaving a specific grava 10 available where it is required that the bonds lty o a u he wet silicate 1s thorbe fired at low temperatures, so as not to oughly mixed with the dryungred ents m a affect the abrasive or non-slip characteriskneadmg machine. The mixturels then of tics of the tile. I For such materials as the the proper consistency for sha 1n as by ordinary magnesium aluminate spinel, we tam mg or dry press p I} fter the tile 1 utilize clay mixtures adapted to burn to a has n shape 1t may e dried 1n a steam lassy nature, or bondswhich are formed box for a few hours at about 140 C. and by combining the more refractory clays then vitr fiedgond ti ogby heating with various fluxes, such as soda, ma nesia, to approxlmate y 2QQZ Q .,,for several hours calcium oxide, lead oxide, barium oxi e, etc., time. Various bond ingredients may be-sub- 20 thus producing complex silicates having a stituted for those above specified, as is well glass fracture and the'qualities of great known in the ceramic art. dura ility and tenacit to hold the grains It has been found that the utility of a tile together. As a speci c exam le of a ceof this type asa safety tread depends largely Jem ma-ad suitable, for use wit ma esium upon two main factors, the sizes of the 2 a uminate sp' incl the following 1ngre d1ents rains employed and the porosity of the tile.

may used in t eproportions specified: t is desirablebthat the surface of thebtile contain a num er of large grains 0 8. out i fi i parts R i 50 mesh in order to afford a safe foothold 13 g Q a and that these be combined with other rain 80 5 g f B; 55 p sizes which will reduce the porosity o the tile to a safe minimum and aid the bond in A plastic mixture of these materials and strengthening the tile. In the formula above water is formed into a tile shape, dried and speci ed for a spinel tile the abrasive is then fired 1n a ceramic kiln, in accordance made up of 50% of 30 mesh grain, 30% of 86 with the usual practice. The firing treatment 60 mesh and 20% of 120 mesh. The porosity I may involve heating the ware at approxiof this tile as determined by water absorpmately cone 12 for several days and then tion is about 8 to 10% by volume. We find slowly cooling, this procedure resulting in it desirable to combine such grain sizes as to the formation of a glassy or vitreous mass give a porosity of from 5 to 20%. In this intimately uniting the spinel granules into a way we keep the grains largely isolated so 'unitary but porous structure in which the that the bond between the grains will not anti-slipping grains constitute the wear-reprevent the abrasive material from getting ceiving part of the surface and preferably a good hold on footgear. This porositythe major portion by volume of the tile. arises from the fact that in the firing oper- 45 We have also found that low fusin abraation the ceramic bond shrinks into a dense sive materials may be employed and yet a vitreous mass in the form of walls and sepatile of high bond strength and tough wearrated posts which tie together the adjacent resistin characteristics obtained. This is surfaces of the grains. aocomp ished by employing a bond which is Due to a-slight reaction between the bond capable of uniting integrally with the. and certain of the available grain materials, grains below the fusion temperature of the such, for'example, as is found in the maggranular material and preferably reacting nesium aluminate spinel tending to react with or dissolving the surface layer of the with the fused clays to form various comgrain to form a strong intermediate la er. plex compounds, the materials are in such 55 :arnet and beriyl are examples of this 0 ass instances bonded -into a substantiall inteof materials. 11 order to bond garnet andgral mass having a tenacious and urable beryl, which melt or become deleteriously structure which will withstand pedestrian affected at a temperature below that of the wear for an indefinite time. It is our inordinary ceramic operation, as above detention to utilize in so far as possible such scribed, we propose to use various silicate combinations of bonding materials for each mixtures capable of forming a glassy bond type of abrasive grain chosen that an inteat a low temperature. 1 gral union will be had, this characteristic As a specific example of a tile of beryl of course being modified or determined by united by a durable silicate bond, which is the physical properties of the abrasive emsubstantially insoluble, the following 'forployed, We therefore are able to obtain 9 suficient tile strength, although using a low.

fusing abrasive material by selecting a deramicbond which is fusi le at a still lower temperature and preferably is capable of the bond itself should receive some wear and occasionally break away to expose fresh and sharp grains on the surface, and so avoid detrimental loading of the tile pores and glazin .of the surface.

Having described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A non-slip tile comprising wear-resisting abrasive granular material of a hardness between quartz and crystalline alumina and a ceramic bondin material integrally united by heat into an a rasive, wear-resisting and substantially integral mass, in which the granular material constitutes a substantial proportion of the surface of the tile and the bond is capable of permitting :enewal of the safety characteristics of the tread surface. 2. A non-slip tile comprising abrasive granular material of-a hardness between 7 and 9 on Mohs scale and a high burned ceramic bonding material integrally united into a non-slip, wear-resisting mass in which the ranular material constitutes the major portion of the volumeof the tile.

3. A non-slip tile comprising wear-resisting, crystalline anti-slipping granular material of a hardness between quartz material of a hardness between beryl bonded by a vitrifie alumina bonded together by an alkaline silicate bond into a porous mass, in which the granular material receives the major portion of the tread wear.

4. A non-slip tile comprising abrasive granules of material having a hardness between quartz and alumina and a ceramlc bond' adapted to resist pedestrian wear which may be matured b heat at a temperature belowthe fusion point of said granular material, the major portion of said granules being between 30 and 120 mesh in slze, and

the bonded mass having an absorption between 5% and 20%.

5. A non-slip tile comprising wear-resisting, anti-slipp ng granular material having a hardness greater than 7 on Mohs scale bonded together by a vitrified alkaline silicate bond.

6. A non-slip, tile comprising granular and 9 on Mohs scale which softens below 1200 C., bonded by a vitrified alkaline silicate bond.

7. A non-slip tile com rising granular d clay and alkaline silicate bond.

8. A non-slip tile comprising abrasive material, which has a hardness between quartz andcrystalline alumina'and is fusible below 1200 0., and a high burned insoluble bond. including sodium silicate, said abrasive material constitutin the major portion of the tread surface an being between'30 and 120 screen mesh in size and the tile having a water absorption of 5 to 20% by volume.

Signed at Worcester, Massachusetts, this 5th day of Nov. 1920.

A. ALBERT KLEIN.

MILTON F. BEECHER. 

